We have, 180° = π Radians
∴ 1° = (

π

180

) radians
(i) 25° = (

π

180

×25) radians =

5π

6

radians
(ii) As we know, 30' = (

30

60

)° = (

1

2

)°
∴ - 47° 30' = - (47

1

2

)° = - (

95

2

)°
⇒ - (

95

2

)° = - (

95

2

×

π

180

) radians =

−19π

72

radians
(iii) 240° = (

π

180

×240) radians =

4π

3

radians
(iv) 520° = (

π

180

×520) radians =

26π

9

radians